Aftertreatment systems are an important technology for reducing harmful emissions from internal combustion engines. Aftertreatment systems generally include a source of storage for reductant (particularly diesel exhaust fluid) and a dosing unit that includes a pump unit for pressurizing the reductant. The aftertreatment systems may also include a metering unit for providing a controlled amount or rate of reductant into a stream of exhaust and an injector, which provides a reductant solution to a decomposition region of an exhaust flow path located upstream of an aftertreatment component (for example, a selective catalytic reduction catalyst).
Various aftertreatment systems utilize liquid-only (i.e., non-air-assisted) dosing units to inject a reductant such as diesel exhaust fluid into a stream of exhaust within an exhaust pipe. Such systems currently employ tangential and/or wall injection methods, which require hardware that enables recirculation zones and nucleation sites for urea deposits to grow. For example, a nucleation creator (i.e., a downstream mixing plate) is currently used to achieve uniformity of diesel exhaust fluid in the exhaust stream prior to reaching the aftertreatment component.